Database.set_clusters(clusters=None, **legacy_clusters)

Persist reusable shock clusters on the database.

Parameters:

• clusters – Mapping of set -> cluster name -> members, using supported set aliases. Members remain lists for common sets. Regional sets accept region -> list mappings; omitted regions select nothing. A list on a regional set is intersected with each region’s domain.

• **legacy_clusters – Backward-compatible cluster payload passed as keyword arguments.

For a common classification, define each cluster as a list of labels:

db.set_clusters({"Activity": {"selected": ["A1", "A2"]}})

Special case: regional classifications

Cluster definitions follow the shape of the corresponding set. For regional activity domains {"IT": ["A1", "A2"], "DE": ["A1", "A3"]}, use:

db.set_clusters({
    "Activity": {
        "selected": {"IT": ["A2"], "DE": ["A3"]},
        "Italy only": {"IT": ["A1"]},
    }
})

Each region-code pair is validated. {"IT": ["A3"]} is rejected even though A3 exists in Germany. Unknown regions and codes are rejected before the stored clusters change. An omitted region selects no members; a same-named explicit definition replaces the complete earlier cluster, without filling omitted regions from it.

A list remains accepted as shorthand on regional sets:

db.set_clusters({"Activity": {"shared selection": ["A1", "A2"]}})
db.clusters["Activity"]["shared selection"]
# {"IT": ["A1", "A2"], "DE": ["A1"]}

The shorthand is intersected with each region’s domain, including empty lists where no supplied code exists. Codes absent from the entire domain are rejected. Common/global sets retain the existing list representation. Set aliases and legacy keyword payloads are supported. Nested input/output lists are copied independently.

Shock expansion respects these regional definitions for activity, commodity, sector and final-demand axes. It selects actual matrix nodes, never a padded region-by-item grid. A literal code absent from all selected regions is an error; a regional cluster with no members in those regions selects nothing.

See the clusters guide for examples.